The reason Zadkiel had asked for the time wasn’t that he didn’t feel ready. He didn’t trust Tia because she was Irvin’s witch and he had a lot to discuss with Abel before making a decision. He also wanted to see that file in Irvin’s office before making some witch stop his heart. For all he know, she could be lying about his immortality.
The next day at training went as tiring as the first day and Zadkiel got hold of his mind-controlling thing. He was taking less time than usual to make Abel do whatever he wanted him to do. This time without him even realizing it as if he was caught in a trance.
After the training he sat with Abel to discuss what he should do because Abel was the only person he could trust with closed eyes, everyone else seemed to have some hidden agenda behind their love for him.